138
Staphylococcaceae Representatives
Staphylococcus aureus
Characteristics of the Disease
During 1982 and 1983, mortalities occurred among silver carp, Hypophthalmichthys
molitrix, at a farm in India. These mortalities were associated with pronounced eye
disease, with the cornea becoming reddish, due to vascularisation, and then opaque.
Thereafter, there was degeneration of the eye tissues, leaving a hollow cup. The
brain and optic nerves were affected. In addition, diseased fi sh became lethargic and
darker in colour (= melanosis). The internal organs did not appear to be affected
(Shah and Tyagi 1986 ). Bacteria, were cultured, and Gram-positive cocci identifi ed,
and equated with Staphylococcus aureus (Shah and Tyagi 1986 ). Subsequently,
jaundice in African sharp-tooth catfi sh, Clarias gariepinus, has been associated
with Sta. aureus (Oladele et al. 2012 ).
Isolation
Eye and brain tissue revealed the presence of bacteria. However, the precise isolation procedures were not stated (Shah and Tyagi 1986 ).
Characteristics of the Pathogen
From this description, an identifi cation of Sta. aureus was achieved (Shah and
Tyagi 1986 ). However, it is apparent that there are insuffi cient data to differentiate
between Sta. aureus and Sta. intermedius (Kloos and Schliefer 1986 ).
Disease Control
Water Disinfection A bath of potassium permanganate (1 ml/l) for 5–10 min,
together with treating the pond water with 250 mg/l of lime and 1 mg/l of potassium
permanganate every fourth day, was considered effective at halting mortalities,
except with advanced cases of the disease (Shah and Tyagi 1986 ).
Box 3.23: Staphylococcus aureus
The cultures comprise Gram-positive cocci, which produce coagulase and
phosphatase, degrade blood (ß-haemolysis) and DNA, and ferment glucose
and mannitol. Zones of opalescence develop around (black) colonies on Baird
Parkers agar.
3 Aerobic Gram-Positive Rods and Cocci
Staphylococcaceae Representatives
Staphylococcus aureus
Characteristics of the Disease
During 1982 and 1983, mortalities occurred among silver carp, Hypophthalmichthys
molitrix, at a farm in India. These mortalities were associated with pronounced eye
disease, with the cornea becoming reddish, due to vascularisation, and then opaque.
Thereafter, there was degeneration of the eye tissues, leaving a hollow cup. The
brain and optic nerves were affected. In addition, diseased fi sh became lethargic and
darker in colour (= melanosis). The internal organs did not appear to be affected
(Shah and Tyagi 1986 ). Bacteria, were cultured, and Gram-positive cocci identifi ed,
and equated with Staphylococcus aureus (Shah and Tyagi 1986 ). Subsequently,
jaundice in African sharp-tooth catfi sh, Clarias gariepinus, has been associated
with Sta. aureus (Oladele et al. 2012 ).
Isolation
Eye and brain tissue revealed the presence of bacteria. However, the precise isolation procedures were not stated (Shah and Tyagi 1986 ).
Characteristics of the Pathogen
From this description, an identifi cation of Sta. aureus was achieved (Shah and
Tyagi 1986 ). However, it is apparent that there are insuffi cient data to differentiate
between Sta. aureus and Sta. intermedius (Kloos and Schliefer 1986 ).
Disease Control
Water Disinfection A bath of potassium permanganate (1 ml/l) for 5–10 min,
together with treating the pond water with 250 mg/l of lime and 1 mg/l of potassium
permanganate every fourth day, was considered effective at halting mortalities,
except with advanced cases of the disease (Shah and Tyagi 1986 ).
Box 3.23: Staphylococcus aureus
The cultures comprise Gram-positive cocci, which produce coagulase and
phosphatase, degrade blood (ß-haemolysis) and DNA, and ferment glucose
and mannitol. Zones of opalescence develop around (black) colonies on Baird
Parkers agar.
3 Aerobic Gram-Positive Rods and Cocci